Lithium cobalt oxide has two polymorphs that display different electrochemical properties despite their identical redox reactions: a high-temperature phase having a layered structure (LiCoO2; HT-LCO) and a low-temperature phase with a spinel-framework (Li2Co2O4;LT-LCO). The synthetic conditions of the single-phase LT-LCO were determined by thermogravimetric (TG) analysis performed on the solid-state reaction of Li2CO3 and Co3O4.The results revealed that LCO synthesis was a second order reaction with the activation energy of Ea = 150 kJ mol −1 and preexponential factor of A = 9.2 × 10 7 s −1 . XRD studies indicated that low temperature synthesis below 350 °C is necessary to obtain the single-phase LT phase, because the HT-phase fraction increased with increasing synthesis temperature. Virtually single-phase LT-LCO obtained by calcining at 325 °C for 240 h exhibited zero-strain lithium insertion. These results contribute towards the establishment of a synthetic method for novel materials with reduced spinel structure.